<button class="c-button">
  <span class="c-main">
    <span class="c-ico"><span class="c-blur"></span> <span class="ico-text">+</span></span>
    button
  </span>
</button>

<style>
/* From Uiverse.io by zebra76966 - Tags: button, dark, 3d button */
button {
  border: none;
}

.c-button {
  background: linear-gradient(140deg, rgba(75, 118, 200, 1) 0%, rgba(31, 70, 145, 1) 100%);
  border-radius: 45px;
  font-size: 25px;
  text-align: left;
  padding: 11px 0px 11px 0px;
  border: 4px solid rgb(37, 37, 37) !important;
  border-style: outset;
  box-shadow: -6px -5px 18px rgba(255, 255, 255, 0.1);
  cursor: pointer;
}

.c-button .c-main {
  border-radius: 45px;
  color: rgba(255, 255, 255, 1);
  padding: 11px 25px 11px 2px;
  box-shadow: inset 0px 0px 5px rgba(17, 17, 17, 0);
  transition: all 0.5s ease-in-out;
  border: 1px solid transparent;
}

.c-ico .c-blur {
  background: linear-gradient(318deg, rgba(75, 118, 200, 1) 0%, rgba(31, 70, 145, 1) 100%);
  border-radius: 100%;
  margin-left: 0;
  padding: 8px 23px;
  filter: blur(1px);
  text-align: center;
}

.c-ico {
  position: relative;
  margin-right: 20px;
}

.c-ico .ico-text {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
}

/* Hovering */

.c-button .c-main:hover {
  box-shadow: inset 0px 0px 5px rgba(17, 17, 17, 0.6);
  border: 1px solid rgba(26, 26, 26,0.5);
  color: rgba(255, 255, 255, 0.5);
}

</style>
